The fixes to Java Runtime Environment (JRE) 1.3.1, 1.4.2, 5.0 and 6.0 plug holes that attackers could use to bypass security restrictions, manipulate data, disclose sensitive information or compromise an unpatched machine. Among the JRE bugs, Sun said in several security advisories, are two that allow attack code from malicious sites to make network connections on machines other than the victimized computer. One possible result, according to a paper by several Stanford University researchers that was cited by Sun: circumvented firewalls.
Other vulnerabilities in JRE and Java Web Start, a framework that lets Java-based applications launch directly from a browser, could be used by attackers to read local files, overwrite local files and hide Java-generated warnings.
Although Sun does not assign threat scores or label its advisories with terms such as "critical" or "low," Danish bug tracking vendor Secunia collectively tagged the five advisories and their 11 patches as "highly critical," its second-highest ranking.
Some of the vulnerabilities are limited to specific JRE versions, but pulling action items from the advisories is difficult since Sun does not use an easy-to-understand grid as does Microsoft, for instance, to indicate affected software. Neither JRE nor Web Start includes an automatic update mechanism; users must manually download and apply the updated versions Sun has posted on its Web site here.
Mention of Mac OS X was, as usual, absent in the security advisories. Sun does not post updated editions of JRE and other Java components for the Mac operating system. Instead, Apple Inc.'s implementation of Java requires that the company provide Java fixes as part of its own security updates. That's been a sticking point with some Mac users, who have expressed concern that Apple has not updated its Java code since February.